Non-contact rotary fader

ABSTRACT

A rotary fader apparatus includes a fader control knob that is directly attached to the rotor of a non-contact electrical motor. The apparatus may produce a fade effect based on the rotational position of the fader control knob and may be automated through signals to the motor. Such a rotary fader apparatus may be used, for example, in audio mixing applications to provide automated or manual rotary control of track fading. The motor may also be used to alter the feel of the movement of the fader control knob and/or provide tactile feedback in response to mixing parameters or signal properties.

BACKGROUND

In audio processing and other electrical signal controls, a typicalfader is a device, element, or interface that enables user-control ofthe amplitude of various input signals. For example, a set of audiofaders may allow a processing engineer to selectively and smoothlyadjust the amplitude for a number of individual input signals beforecombining (or mixing) them into one or more output signals forrecording. Typical faders are constructed using either linear sliders orrotary knobs physically attached to various actuation components througha number of gears, chains, belts, bands and/or potentiometers. In thecase of motorized faders, actuation components connected to electroniccontrol circuitry or programming may drive the physical position offader controls in response to desired signal level conditions.Historically, this has been accomplished through physically connectedcontrol mechanisms.

SUMMARY OF THE DISCLOSURE

The present inventors have recognized a need for a motorized rotaryfader that is simple in design and capable of offering an enhanced andcustomizable user-experience. Accordingly, the following disclosuredescribes systems, methods, devices, and computer media that may help toproduce a more efficient, reliable, and user-controllable faderexperience through a motorized rotary fader. Additionally,susceptibility to wear along with a coggy or gritty feel that isnecessarily a part of physically coupled faders due to gears, pulleys,sensors, electrical connections and/or contact motors may be reduced oreliminated by the rotary fader of the present disclosure. A furtheradvantage of the rotary fader is the substantial removal of mechanicalinterference that allows for more smooth and precise control of therotary fader in terms of its position, motion and/or applied torque.Other advantages of the present embodiments will be clear to those ofskill in the art.

In one embodiment, an exemplary fader apparatus includes a fader controlknob directly attached to a rotor of a non-contact motor. The faderapparatus also includes a sensor system configured to detect arotational position of the rotor and control circuitry configured tocause a fade effect in response to detecting the rotational position ofthe rotor.

In another embodiment, an example method for using a fader apparatusinvolves a sensor system detecting a rotational position of a rotor of anon-contact motor, with the rotor being directly attached to a fadercontrol knob. The method also involves control circuitry causing a fadeeffect in accordance with the detected rotational position of the rotor.This fade effect is caused in response to detecting the rotationalposition.

In another example method, a fader apparatus receives a signalrepresenting a desired feel effect for the fader control knob. Themethod also involves the apparatus receiving, from a sensor system, anindication of a user-interaction with the fader control knob. The methodfurther involves responsively controlling a stator current to provide apredetermined proportion of torque associated with the desired feeleffect.

In another example method, a fader apparatus receives a signalrepresenting a desired fade effect. In response to the received signal,the method involves providing a torque sufficient to rotate the fadercontrol knob to a position associated with the desired fade effect.

In another example method, a fader apparatus provides tactile feedbackto a user in response to the position of a fader control knob and/orprogram signals derived from the state of a mixer. These may be inresponse to signals it receives and/or programmable features for mixingparameters along with the user-dialed settings.

In yet another embodiment, an illustrative fader apparatus includes afader control knob attached to a rotor of a non-contact motor. The rotoris configured to provide a force sufficient to rotate the fader controlknob to a position associated with a desired fade effect. Further,current through a stator of the non-contact motor is controlled toprovide a torque of the non-contact motor associated with a desired feeleffect when being operated by a user.

The foregoing is a summary of the disclosure and thus by necessitycontains simplifications, generalizations and omissions of detail.Consequently, those skilled in the art will appreciate that the summaryis illustrative only and is not intended to be in any way limiting.Other aspects, inventive features, and advantages of the devices and/orprocesses described herein, as defined by the claims, will becomeapparent in the detailed description set forth herein and taken inconjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a simplified perspective schematic illustrating elements of arotary fader according to an exemplary embodiment.

FIG. 2 is a top view schematic illustrating elements of a non-contactmotor used by the rotary fader of FIG. 1 according to an exemplaryembodiment.

FIG. 3 is a simplified block diagram illustrating additional elements ofthe rotary fader of FIG. 1 according to an exemplary embodiment.

FIG. 4 is a flowchart showing process steps for operating the rotaryfader of FIG. 1 according to one exemplary embodiment.

FIG. 5 is a flowchart showing process steps for operating the rotaryfader of FIG. 1 according to another exemplary embodiment.

FIG. 6 is a flowchart showing process steps for operating the rotaryfader of FIG. 1 according to yet another exemplary embodiment.

FIG. 7 is a flowchart showing exemplary process steps that may beperformed in combination with the process of FIG. 6.

FIG. 8 is a flowchart showing exemplary process steps that may beperformed in combination with the process of FIG. 7.

FIG. 9 is a flowchart showing process steps for operating the rotaryfader of FIG. 1 according to another exemplary embodiment.

FIG. 10 is a flowchart showing process steps for operating the rotaryfader of FIG. 1 according to still another exemplary embodiment.

FIG. 11 is a waveform illustrating the creation of perceived notches ona fader control knob of the rotary fader of FIG. 1, according to oneexemplary embodiment.

FIGS. 12 a and 12 b are simplified schematic illustrations, each showingan exemplary configuration of the fader control knob of the rotary faderof FIG. 1 being used as an audio recorder according to another exemplaryembodiment.

DETAILED DESCRIPTION

Disclosed herein are systems, devices and techniques. The devices andsystems may include a rotary fader apparatus and the techniques mayinclude processes that use or support the use of such rotary faderapparatuses. In its construction, the rotary fader apparatus may includea fader control knob that may freely rotate, supported solely on asimple low-friction support (e.g., a bearing, bushing, etc.) along ashaft, having preferably virtually no perceptible opposition to motionand a wear expected to exceed decades of use. In alternate embodiments,a small amount of simulated opposition to motion, enough to provide atactile sensation to a user without interfering with a substantiallynon-contact control described below, may be imposed on the fader controlknob and/or the shaft. Other than such supporting structures, thisdesign may allow elimination of substantially all physical connections(in any form, mechanical or electrical) required for sensing positions,moving/rotating or controlling the feel of the fader control knob.

The disclosure is separated into two main sections. The first sectiondiscusses features of example and systems. The subsequent sectiondiscusses techniques, methods, and procedures. Although the sectionregarding example methods makes reference to elements described in thesection regarding the example systems, this is not intended to implythat the example systems and methods must be used together. Rather, theexample methods may be carried out using any suitable system orcombination of systems. Likewise, procedures other than those outlinedin the example methods may be carried out using the described examplesystems.

I. EXAMPLE SYSTEM AND DEVICE ARCHITECTURE

FIG. 1 displays one arrangement of elements in a rotary fader 100according to an example embodiment. As shown, the rotary fader 100includes a fader control knob 102 directly coupled to a shaft 104 thatincludes or is fixedly attached to a cup shaped magnetic rotor 106. Asshown, the rotor 106 surrounds stator coils 108, which may be configuredto receive the signals in accordance with the position and/or force onthe rotor 106. Additionally, as shown, a mechanical pushbutton 110 isdisposed below the rotor 106. The rotary fader 100 also includes a topplate 112 beneath the fader control knob 102 and concealing the rotor106, the stator coils 108, and the shaft 104 of the rotary fader. Therotary fader 100 further includes a bottom plate 114, providingmechanical support for the pushbutton 110. Although not shown overtly inFIG. 1, additional elements, including mechanical support structures andelectronics may be used in the embodiment shown in FIG. 1.

The fader control knob 102 may be any type of rotary control interfacewith which a user may interact. In this context, the word “rotary” maybe used to describe the fact that the fader control knob 102 is movablein a rotational pattern. Such a rotational pattern may be preferablycircular. However, the rotational pattern is not so limited. Inalternate embodiments, other rotational or substantially rotationalpatterns may be used. Additionally, the fader control knob 102 need notbe circular, as it is shown in FIG. 1. Rather, knobs of any shape may beused in an example embodiment. Furthermore, in some configurations, thefader control knob 102 may include one or more position indicators toshow the relative position of the rotary fader 100. Such indicators maybe physical (e.g., a point, divot, scallop, bar) or electronic (e.g., alight on the fader control knob 102, a light on the top plate 112, etc.)in nature. In some electronic implementations, a plurality of possibleindicator positions may be disposed around the fader control knob 102,and one or more particular indicator positions may be activated inaccordance with how the rotary fader 100 is currently being applied.

The fader control knob 102 may be fixedly coupled to the shaft 104. Insome embodiments, the fader control knob 102 and the shaft 104 may be asingle molded element. In other cases, the fader control knob 102 may bephysically attached such that any force applied to the fader controlknob is applied to the shaft 104 with substantially equal magnitude. Itis noted that some force or motion may be reduced due to slippage,material deformations, or other practical necessities. Such attachmentmay be keyed, frictional, adhesive, brazed, or any other knownattachment between two elements. Similarly, the rotor 106 and the shaft104 may be fixedly attached either as a single piece or through any typeof fixed connection. By such attachments, any movement or force at thefader control knob 102 may be directly translated to the rotor 106 andany movement or force at the rotor 106 may be directly translated to thefader control knob.

In addition to being rotationally movable, the fader control knob 102may be movable in other ways. For example, the fader control knob 102may be at least slightly elevated above the top plate 112 in order toallow clearance for pressing down and/or pulling up of the rotarycontrol knob. In an example embodiment, the pushbutton 110 may bedisposed such that a downward force applied to the fader control knob102 may cause actuation of a surface of the pushbutton and, thereby,cause activation of any element under control of the pushbutton. Inother embodiments, the pushbutton 110 may be replaced by a controlstructure that responds to upward force or motion on any part of theassembly involving the fader control knob 102, the shaft 104 and/or therotor 106. For example, a lever may be attached below the rotor 106. Asanother example, a second pushbutton may be attached between theunderside of the top plate 112 and a top of the rotor 106, such thatupward motion actuates the top pushbutton. Any other arrangement ofphysical actuators or sensors may be used in an example embodiment toallow additional ways to send control signals from the rotary fader 100.In still other embodiments, both upward and downward movement sensorsmay be included or additional sensors may be included to detecttranslational (non-rotational) movements in directions other thanvertical. However, some embodiments may include no translationalmovement sensors, and rotational movement alone may be controlled ormeasured.

The shaft 104 may be constructed of any material that has sufficientmechanical strength to fixedly attach the fader control knob 102 to therotor 106. In some preferable embodiments, the shaft 104 may beconstructed of a lightweight material to avoid adding inertia to themovement of the assembly of the fader control knob 102, the shaft andthe rotor 106. In other embodiments, heavier materials may be used toimprove the mass, strength or reliability of the above mentionedassembly. As shown in FIG. 1, the shaft 104 may be cylindrical in shapeand sufficiently long to extend through the stator coils 108. Othershapes and sizes of the shaft 104 may be used in place of thecharacteristics shown. Although the shaft 104 is depicted as relativelylong in FIG. 1, the shaft may be preferably only as long as needed toextend through the stator coils 108. Since, in some embodiments, thestator coils 108 may be affixed to the underside of the top plate 112,the shaft 104 may be quite short. Additionally, since the fader controlknob 102 and/or the rotor 106 may be integrally connected to, orfabricated as a single piece with the shaft 104, the shaft may beconsidered a feature of the fader control knob and/or the rotor ratherthan a separate element, in some embodiments. In such a case, only asingle connection (or no connection at all) may be made to couple thefader control knob 102 and the rotor 106.

Additionally, the rotor 106 and the stator coils 108 may constitute atleast part of an electrical motor (described in FIG. 2 below). In anillustrative embodiment the motor may be a brushless direct currentmotor (BLDC motor) or a contactless motor in which electrical current isnot drawn from physical electrical connections to the rotor 106. In sucha motor, the rotor 106 may include magnetic components disposed on thevertical portions of the cup-shaped body of the rotor. Such magneticportions may be permanent or electrically-induced magnetic materialsarranged such that north and south poles alternate around thecircumference of the cup portions that encircle the stator coils 108.For example, FIG. 2 shows a top view (a corresponding perspectivedirection is labeled “FIG. 2” in FIG. 1) of a rotor 208, with twelvemagnetic poles (“N” and “S”) alternating around a nine-coil stator 206in a non-contact motor 200. Although the poles are shown in FIG. 2 ashaving sharp cutoffs between the north and the south polarities, theactual changes may be gradual between each pair of poles, such that aroughly sinusoidal magnetic flux may be established around thecircumference of the rotor 208. Electromagnetic laws may show that, inthe arrangement shown in FIG. 2, the motion of the rotor 208 may bedirectly related to the current through the coils of the stator 206.

In particular, the torque (or rotational force) produced in the motor200 (or a similar BLDC motor) is proportional to the cross-productbetween a stator flux (that is, flux generated by an applied currentthrough the motor windings of the stator 206) and a rotor flux (that is,flux generated due to the magnetic structure of the rotor 208). Whencurrent is applied to the coils of the stator 206, a magnetic field isgenerated through the stator. By controlling the current applied to thestator 206 to produce a particular stator magnetic field, a torque maybe induced in the rotor 208, whereby a force may be applied to align amagnetic field of the rotor with the stator magnetic field. For a fixedlevel of magnetic field (or current), the maximum torque may be obtainedwhen the magnetic fields for the stator 206 and the rotor 208 areorthogonal or at locations where the sign of the angular displacementproduces either a clockwise or counterclockwise rotation from the topperspective of FIG. 2.

Specifically, in a three-phase system with windings of the stator 206grouped as either a, b, or c the relationship between the (scalar)values for the current through the windings a, b and c (i_(a), i_(b),and i_(c), respectively) of the stator and the complex (vector) statorcurrent (i_(s)) may be defined by the relation:

{right arrow over (i)} _(s) =i _(a) +e ^(jπ2/3) i _(b) +e ^(jπ4/3) i_(c) =i _(r) e ^(jπφr)

In addition to describing the currents as phasors having magnitude andangle, it may be also useful to reference the phasor current in relationto the rotating frame of reference referred to by an in-phase axis(called the d-axis, aligned with the rotor flux) and a quadrature axis(called the q-axis). The stator current may be decomposed intocomponents projected onto the d- and q-axes, or a flux component andtorque component, respectively, with the axes being aligned with areference point such as the center of rotation for the rotor 208.

In the embodiment shown in FIG. 2, the rotor 208 may have a roughlysinusoidal or trapezoidal distribution varying along the twelve poles,described above. Therefore, once a current vector is supplied, sixangular locations where the (local) flux vector is in alignment with thecurrent vector, or six stable angular positions for the rotor position,may be created. When the rotor 208 is turned physically out of such astable condition, while the fixed current vector continues to besupplied, a torque may be supplied until the rotor is turned halfway toan adjacent stable condition (40° for the illustrated embodiment), atwhich point, the torque may be working in the same direction as therotation. Thus, a smooth sinusoidal cogging torque may be experiencedwith several stable positions separated by local areas of instability,as explained below.

Referring to FIG. 11 in conjunction with FIG. 2, an exemplary graphicalillustration 1100 of a torque waveform as a function of a sensedposition of the rotor 106, 208 is shown, in accordance with at leastsome embodiments of the present disclosure. Specifically, the graphicalillustration 1100 plots a torque command on Y-axis 1102 against anangular position of the rotor 106, 208 on X-axis 1104. The graphicalillustration 1100 further shows two exemplary notches 1106 and 1108,each having a stable position 1110. Specifically, the notches 1106 and1108 may be created by generating a current vector, as explained above,to create a torque pattern as a function of sensed position of the rotor106, 208 based upon feedback from the Hall-sensors. Such a torquepattern may create the stable position 1110 in each of the notches 1106and 1108. Furthermore, the shape of the notches 1106 and 1108 maydetermine the characteristics of those notches. For example, the notch1108 may have a wider range compared to the range of the notch 1106.Similarly, the spacing between the notches may be decreased or increasedby altering the shape or position of those notches.

Notwithstanding the fact that the graphical illustration 1100 shows onlytwo notches (e.g., the notches 1106 and 1108) having specific shapes, inother embodiments, notches having various other shapes may beimplemented. For example, in at least some embodiments, the notches mayhave a sinusoidal shape of the torque against sensed position curve.Advantageously, by custom defining the notches 1106 and 1108, a familyof configurable notches (also referred to herein as configurabledetents) may be created where the rotor 106, 208 may “stick” at closelyspaced intervals. Further, the notches 1106 and 1108 may be programmablein terms of amplitude, width, density, and shape of the notch.Additionally, the notches 1106 and 1108 may be placed anywhere in arotation of the fader control knob 102 by defining the torque waveformsas a function of sensed position (e.g., the notches 1106 and 1108) withno dependence on the configuration of the motor 200.

Returning back to FIG. 2, in some embodiments, markings on the top plate112 of the rotary fader 100 may provide indications of the notches andwhere the stable positions are located (with respect to some marking orfeature on the fader control knob 102). Such markings may includedescriptors of the levels. For example, an audio fader in which eachnotch represents a decibel sound level may include markings that showwhat decibel level is associated with each notch. As will be described,notches may change position, number, and other characteristics.Therefore, the markings on the top plate 112 may be changeable (moving,dynamic, displayed, virtual, etc.) to show the current settings of therotary fader 100. Additionally, if the fader control knob 102 is allowedto turn multiple revolutions, the markings may change depending on whichrevolution the fader control knob is currently operating.

Correspondingly, if the current through the coils of the stator 206 ischanged in a way that alters the current vector alignment, a physicalrotation may be produced in the motor 200 by shifting the phase of thecurrent vector (of sufficient magnitude to overcome friction, rotorinertial mass, or other opposition to motion) through six full cycles,producing one full physical revolution of the rotor 208. With thistechnique, the rotary fader 100 may arbitrarily position the rotor 208by driving or holding the current vector at a phase corresponding to anydesired physical position or movement.

Furthermore, in cases where the fader control knob 102 is held or movedby a user or other outside force, an arbitrary torque (within ratedlimits of the motor 200) may be produced by varying the magnitude andphase of the current vector corresponding to that angular location.Specifically, for some motor constant, k_(T), that depends on the motorparameters, a programmable torque may be produced with either a positiveor a negative value, T described by the equation:

T=k _(T)|{right arrow over (l _(s))}| sin(φ−θ),

where θ is the physical angular direction of the d-axis, and φ is thephysical angular direction of the current.

Although FIG. 1 shows a considerable gap between the stator coils 108and the top plate 112, in some embodiments, the stator coils 108 may bein close proximity, or attached directly to the top plate. In such anembodiment, circuitry that controls and/or monitors the current in thestator coils 108 may be included on the underside of the top plate 112.Indeed, such processing circuitry, the stator coils 108, and othermechanical constructs may be treated as a single integrated“stator-support unit.” Similarly, the rotor 106, 208, the fader controlknob 102, and the shaft 104 may also be treated as an integrated,preferably solid-state “rotor-knob unit” that within itself, may onlyrequire the presence of magnets for operation. Furthermore, therotor-knob unit may freely rotate in a substantially non-contactcoupling with the stator-support unit. The “non-contact” nature of therotor-knob unit and the stator-support unit may be further described interms of exchange of energy between the stator-support unit and therotor-knob unit. Specifically, by virtue of having a non-contactexchange of energy between the rotor-knob unit and the stator-supportunit, no physical electrical connection or mechanical mechanism may berequired for transferring energy (e.g., torque in the direction ofrotation or stationary torque from which energy may be derived ifrotation is allowed) into the rotor-knob unit. Rather, energy may beimported into the rotor-knob unit by way of a magnetic coupling acrossthe gap separating the rotor-knob unit and the stator-support unit.Therefore, in at least some embodiments, even though a mechanical orelectrical component (e.g., a support component) may be provided betweenthe rotor-knob unit and stator-support unit, the energy transferred intothe rotor-knob unit may be entirely magnetic. Furthermore, it is to benoted that the Hall-sensors described above may also be magneticallycoupled to the rotor 106, 208. Therefore, both energy transfer into andinformation transfer out of the rotor-knob unit may require no physicalconnection or contact between the rotor-knob unit and the stator-supportunit.

In one example embodiment, the motor 200 may be a three-phase brushlessmotor from Nidec Corp. (part number 20N210F020), although other types ofmotors and specific motor parts may be used and are anticipated by thepresent inventors. One advantage of the motor 200 is the inclusion ofHall effect sensors integrated into the circuit board that attaches tothe coils of the stator 206. One function of Hall effect sensors is tomonitor the rotational position of the rotor 106, 208 with respect tothe stator 206 and/or with respect to some initial position. In thiscapacity, the Hall effect sensors may be used to track movements of therotor 106, 208 (and, therefore, the movements of the fader control knob102) to determine how to fade or alter an input sound signal. One set ofexample relative positions for three Hall-effect sensors are shown aselement 204 in FIG. 2. As shown, the sensors may each detect the inducedHall effect from a different magnetic polarity of the rotor 106, 208that happens to align with the sensor.

In some embodiments, Hall sensors, or other sensors (e.g., light orsound-based proximity sensors, capacitive or magnetic air-gap sensors,actuators, motion sensors, mechanical connectors) may be used fordetecting translational movement of the rotor 106, 208 or other elementsof the rotary fader 100. Translational movement may be movement in anydirection that is not rotational in nature. For example, in embodimentsthat do not include the pushbutton 110, translational sensors may trackthe vertical movement of the rotor 106, 208 to activate variousfunctions of the rotary fader 100. In such an embodiment, severaldifferent functions may be assigned to various vertical positions of therotor 106, 208 (which translate to vertical positions of the fadercontrol knob 102). Additionally, movements of the fader control knob 102or the rotor 106, 208 across the top plate 112 may be measured and usedas a source of additional input signals. For example, the top plate 112may include slots around a through-hole for the shaft 104, so that thefader control knob 102 (along with the shaft 104 and the rotor 106, 208)may be moved along one or a few axes. Each potential position of thefader control knob 102 may be assigned to an input signal ormodification signal for the output of the rotary fader 100. As aparticular implementation case, the fader control knob 102 may bemoveable from left to right, with the rotary fader 100 modifying oneaudio track when the fader control knob is in the left position, andmodifying a second audio track when the fader control knob is in theright position. In order to support such movements, the stator 206 mayalso be moveable across the back side of the top surface 112.

In an exemplary embodiment, the rotary fader 100 also includes variouscomponents and subsystems that function to alter input signals (such asamplifying or attenuating audio signals) in accordance with movements atthe rotary fader. Additionally, the rotary fader 100 may also includemotor-control circuitry configured to cause movements at the rotaryfader based on stored or received input signals.

Turning now to FIG. 3, a block diagram illustrating elements related tofunctional components of a rotary fader 300 is shown, in accordance withat least some embodiments of the present disclosure. In addition to thecomponents described in FIG. 1, the rotary fader 300 may include aprocessor 302, electronic storage 304, rotational position sensors 308,translational position sensors 310, and communication interfaces 312,all communicatively connected through bus 314. Certain data elements mayalso be considered part of the rotary fader 300 either because theseelements are physically stored or received as non-transitory media, orbecause the rotary fader affects them in a physically measurable way.For example, FIG. 3 shows program instructions 306, input signal 316,output signal 318, and control input 320 as elements that are a part of,or associated with, the rotary fader 300. Although signals like theinput signal 316, the output signal 318, and the control input 320 arelikely dynamically varying electrical properties, they are stillphysical signals that represent other tangible properties (such as soundwaves or controller positions).

The processor 302 may include any processor type capable of executingthe program instructions 306 in order to perform the functions describedherein. For example, the processor 302 may be any general-purposeprocessor, specialized processing unit, or device containing processingelements. In some cases, multiple processing units may be connected andutilized in combination to perform the various functions of theprocessor 302. In at least some embodiments, the processor 302 may be aPiccolo microcontroller by Texas Instruments Inc., although other typesof microcontrollers and/or processors may be used in other embodiments.

The electronic storage 304 may be any available media that may beaccessed by the processor 302 and any other processing elements in therotary fader 300. By way of example, the electronic storage 304 mayinclude RAM, ROM, EPROM, EEPROM, NAND-based flash memory, CD-ROM,Bluray, or other optical disk storage, magnetic disk storage or othermagnetic storage devices, or any other medium that may be used to carryor store desired program code in the form of program instructions ordata structures, and which may be executed by a processor. In somecases, the electronic storage 304 may, in some cases, includecomputer-readable media (CRM). When information is transferred orprovided over a network or another communications connection (eitherhardwired, wireless, or a combination of hardwired or wireless) to amachine, the machine may properly view the connection as a type ofelectronic storage. Thus, any such connection to a computing device,processor, or control circuit is properly termed electronic storage (orCRM if the signal is readable by a computing device). Combinations ofthe above are also included within the scope of computer-readable media.

The program instructions 306 may include, for example, instructions anddata capable of causing a processing unit, a general-purpose computer, aspecial-purpose computer, special-purpose processing machines, or remoteserver systems to perform a certain function or group of functions.These instructions need not be digital or composed in any high-levelprogramming language. Rather, the program instructions 306 may be anyset of signal-producing or signal-altering circuitry or media that arecapable of preforming function such as those described in the examplemethods in this disclosure.

As described above, the rotational position sensors 308 and thetranslational position sensors 310 may include various types of contactand non-contact detection devices, actuate-able interfaces, and/orcomputing systems. In some cases, these positions/movements may bemeasured by separate devices or systems. In other cases, some or all ofthe functions associated with the rotational and the translationalposition sensors 308 and 310, respectively, may be performed by the samedevices or systems.

For simplicity, the bus 314 is shown in FIG. 3 as a single connectionbetween all elements. However, elements in an exemplary system mayconnect through a variety of interfaces, communication paths, andnetworking components. Connections may be wired, wireless, optical,mechanical, or any other connector type. Additionally, some componentsthat are shown as directly connected to through the bus 314 may actuallyconnect to one another only through some other element on the bus.

The communication interfaces 312 may include, for example, wirelesschipsets, antennae, wired ports, signal converters, communicationprotocols, and other hardware and software for interfacing with externalsystems. For example, the rotary fader 300 may receive text, audio,executable code, video, digital information or other data via thecommunication interfaces 312 from remote data sources (e.g., remoteservers, internet locations, intranet locations, wireless data networks,digital audio databases, etc.) or from local media sources (e.g.,external drives, memory cards, specialized input systems, wired portconnections, wireless terminals, microphones, speakers, etc.). Examplecommunication networks include Public Switched Telephone Network (PSTN),Public Switched Data Network (PSDN), a short message service (SMS)network, a local-area network (LAN), a voice over IP (VoIP) network, awide area networks (WAN), a virtual private network (VPN), a campus areanetwork, and the Internet. An example network may communicate throughwireless, wired, mechanical, and or optical communication links. Manyother communication networks may also be suitable for the embodimentsdiscussed herein.

Furthermore, the communication interfaces 312 may includeuser-interfaces to facilitate receiving user-input and user-commandsinto the rotary fader 300 and outputting information and prompts forpresentation to a user. Although the user-interfaces of thecommunication interfaces 312 typically connect with human users, theseuser-interfaces may alternatively connect to automated, animal, or othernon-human “users.” Additionally, while input and output are describedherein as occurring with a user present, the user-interfaces need notpresent information to any actual user in order for present functions tobe performed. User-input may be received as, for instance,wireless/remote control signals, touch-screen input, actuation ofbuttons/switches, audio/speech input, motion input, lack of interactionfor a predefined time period, and/or other user-interface signals.Information may be presented to the user as, for instance, video,images, audio signals, text, remote device operation, mechanicalsignals, media file output, etc. In some cases, separate devices may beoperated to facilitate user-interface functions.

The rotary fader 100, 300 may include many other features in accordancewith various embodiments. For instance, some embodiments may include adedicated power source, not shown. In practice, such a power source mayinclude batteries, capacitors, generators, transformers and/or otherpower providing sources. Other embodiments may include power-connectinginterfaces that are operable to communicate power from external powersources to elements in the rotary fader 100, 300. As another example,the rotary fader 100, 300 may include external protective surfaces orcasing to enclose various parts and devices in the rotary fader. As yetanother example, the rotary fader 100, 300 may include equipment thatmonitors the functions and state of the rotary fader itself, to checkfor malfunction. Further, sensors may also be affixed on, or near, thefader control knob 102 in a position at which the sensors may detect thepresence of a user's hand for a number of potential benefits describedin the next section.

II. EXAMPLE OPERATION

Functions and procedures described in this section may be executedaccording to any of several embodiments. For example, procedures may beperformed by specialized equipment that is designed to perform theparticular functions. As another example, the functions may be performedby general-use equipment that executes commands related to theprocedures. As a further example, each function may be performed by adifferent piece of equipment with one piece of equipment serving ascontrol or with a separate control device.

FIGS. 4-10 illustrate methods according to example embodiments. Althoughthe figures show a specific order of method steps, the order of thesteps may differ from what is depicted. Also, two or more steps may beperformed concurrently or with partial concurrence. Such variations maydepend on the software and hardware systems chosen and the specificembodiment. All such variations are within the scope of the disclosure.Likewise, software implementations may be accomplished with standardprogramming techniques with rule-based logic and other logic toaccomplish the various connection steps, processing steps, comparisonsteps and decision steps.

At block 502, method 500 includes receiving an input signal, such as theinput signal 316. In some cases, the input signal 316 may be stored inthe electronic storage 304 of the rotary fader 300 and received by theprocessing elements through the bus 314. In other embodiments, the inputsignal 316 may be received via the communication interfaces 312 fromlocal or remote sources. The input signal 316 may be received in anyformat or encoding and, therefore, may be translated or reformatted bythe rotary fader 100, 300 (or an element communicatively connected tothe rotary fader) prior to being altered by the rotary fader.

The input signal 316 may include any of various signal types. Forexample, the input signal 316 may include audio, video, electricalcurrent, optical, and/or visual signals, in addition to other signaltypes. In some cases, multiple ones of the input signal 316 may bereceived and altered by the rotary fader 100, 300. For example, if therotary fader 100, 300 receives four video signals that are to be mixedtogether, the rotary fader may assign a translational position of therotary fader to each of the signals so that the user may move the rotaryfader to the assigned position when they desire to alter the respectivesignal associated with the position. As another example, the rotaryfader 100, 300 may be used to mix together two audio signals byassigning a direction of rotation to each signal so that a user may makeone signal more prominent than the other by turning the fader controlknob 102 in the direction assigned to the desired signal and vice versa.The rotary fader 100, 300 may also receive signals that combine morethan one type of media (such as a corresponding audio and video signalfor a single scene) that are to be faded jointly or separately. Signalsmay be received all at once and then edited using the rotary fader 100,300 or the signal may be streamed to the rotary fader one piece at atime.

At block 508, the method 500 involves outputting an output signal thathas been faded according to some set of procedures. The output signal,such as the output signal 318, may include all of the features discussedabove with respect to the input signal 316. In particular, the outputsignal 318 may be any of the signal types and may include multiplesignals or a single signal. The output signal 318, in some embodiments,may include a different number of signals than the input signal 316(e.g., because the signals are mixed together into fewer signals).However, the output signal 318 may typically only include media typesequivalent or substantially equivalent to the types of the input signal316. The output signal 318 may be transmitted in the same way that theinput signal 316 is received and may be processed after being faded, forinstance, to comply with formatting or encoding requirements.

At blocks 402, 504, and 604, methods 400, 500, and 600, respectively,include detecting the rotational position of a non-contact motor'srotor. Block 704 of method 700 includes detecting a position of thefader control knob 102. As described above, the detection of theposition of the rotor 106, 208 and the position of the fader controlknob 102, may be performed by various sensors and devices. Althoughposition of the rotor 106, 208 may be directly detected as the rotorposition and/or the position of the fader control knob 102 (in someembodiments), the detected position may be considered a singleknob/rotor position because of the direct connection between the fadercontrol knob and the rotor. In embodiments where some or a significantamount of flexing, bending, or gap allows the position of the rotor 106,208 to be significantly different from the position of the fader controlknob 102, the rotary fader 100, 300 may detect one position and use itas the position of interest for the rotary fader.

In some embodiments, position detection (of the rotor 106, 208 and/orthe fader control knob 102) may be performed on a periodic basis (e.g.,once a minute, 10 times per second, 20,000 times per second, etc.) toprovide a set of position values ranging in specificity from veryoccasionally to real-time streaming. In other embodiments, the positiondetection is only performed in response to particular stimuli (e.g.,motion detected, contact of the user with the fader control knob 102,input audio signal detected, both input and motion detected, etc.). Instill other embodiments, the detection may be performed on a passivebasis, with the rotary fader 100, 300 constantly detecting positioninformation, even when the information is not being used. Additionally,in some embodiments, the rotary fader 100, 300 may combine both periodicand responsive detection processes to yield a more complete result. Forinstance, the periodic position detection may start with one rate whenneither user-presence nor input signal is detected and then increase tofaster periodic rates when one or both of these stimuli are detected.

In some embodiments, the position of the rotor 106, 208 and/or the fadercontrol knob 102 may be measured only as the result of detectedmovements. For example, if the rotor 106, 208 is moved 60° from a startposition, then a sensor may detect only the movement of the rotor andinfer the final position of the rotor by adding 60° to the startposition. In other embodiments, the position of the rotor 106, 208and/or the fader control knob 102 may be measured directly whether ornot the sensor was aware of the rotor's previous position and withoutthe necessity of movement. For example, the rotor 106, 208 may havecertain markings that are indicative of the absolute value of the rotorposition, rather than a relative movement value, and that are detectableto the sensors (e.g., tiny variations in the magnetic structure of therotor may be measured by comparing Hall sensor signals to factory presetlevels). In embodiments where the rotary fader 100, 300 may bepurposefully turned farther than 360° (i.e., the fade-effect continuesto change after the first revolution of the fader control knob 102 in asimilar way as before the first revolution is completed), the rotaryfader may track the number of revolutions even if the position istracked directly by the sensors.

For Hall-effect sensors, the position may actually be tracked asrelative polarity of the rotor 106, 208 (north or south) in combinationwith the number of times that the polarity has transitioned. Therefore,a full revolution of the rotor 208 in FIG. 2 may produce six peaks andsix valleys in the detected position signal from each sensor, with eachpeak or valley corresponding to either a north or south polarity of therotor from the perspective of the coil(s) associated with the sensor.Hence, the size of a change in position may be counted as the number ofpeaks times the value of each peak (for 12 poles, 60° or π/3 radians)plus the phase difference between the original position and the finalposition. Hall sensors may be used in tracking translational movementsof the fader control knob 102, the shaft 104, and/or the rotor 106, 208as well. For example, if the rotor 106, 208 were moved away from thesensors (e.g., in a downward direction on FIG. 1), then the magneticfield at all of the Hall sensors may reduce, which may not be typicalfor rotational movements. Therefore, by tracking correlated changes inmultiple Hall sensors, the rotary fader 100, 300 may track translationalmovements without making mechanical contact with the moving parts of therotary fader.

In at least some embodiments, the angular position control of the rotor106, 208 may be achieved by using open-loop or closed-loop mechanisms.For example, in an open-loop mode, a drive vector of sufficientmagnitude to move the rotor 106, 208 may be applied to the stator coils108 of the stator 206. By virtue of applying the drive vector, the rotor106, 208 may move its electrical phase into an alignment with the drivephasor. On the other hand, in a closed-loop mode, variants ofproportional, integral and derivative (PID) control may be applied withtuning constants such that an angle of the rotor 106, 208 may be drivenin a rapid and stable trajectory. In at least some embodiments, acombination of the open-loop and the closed-loop modes may beimplemented as well.

At blocks 404, 506, and 706, the methods 400, 500, and 700,respectively, include producing a fade effect in accordance with adetected position of the rotor 106, 208 or the fader control knob 102.The fade effect may be any signal processing that is tunable by therotary fader 100, 300. For example, if the input signal 316 is an audiosignal, the fade effect may alter the amplitude, frequency, phase,timbre, echo, sampling characteristics, speed, equalization, reverb,reverse echo, noise properties, carrier wave dynamics, or beating of aninput audio signal, in addition to various other techniques andcharacteristics. As another example, if the input signal 316 is a videosignal, then the fader effect may facilitate changing the spectralcharacteristics, coherence, brightness, tone, sharpness, contrast,sampling rate, density, proportion, or position of the video signal. Asstill another example, if an electrical input signal is applied to therotary fader 100, 300, then the fade effect may change the voltageamplitude, current amplitude, voltage frequency, waveform, phase,current frequency, dispersion, or DC offset of the signal. For othertypes of the input signal 316, different fader qualities may be used. Insome embodiments, a “fader” may only be considered an audio fadingdevice. In other embodiments, the “fader” may be limited to a singledifferent application.

The altered property of the input signal 316 may be either discrete(i.e., varying at a certain number of perceptible levels) or continuous(i.e., varying at a near-imperceptible fineness between levels, ratherthan conforming to larger discrete levels). For discrete properties,each level of the varied property may be associated with a particularrange of rotational positions. For example, if the altered property onlyhas a single value representing an “on” state and a single valuerepresenting an “off” state, then the rotary fader 100, 300 may (i)designate a central rotational position, (ii) turn off the fade effectwhen the rotor 106, 208 is turned counter-clockwise from the centralposition and (iii) turn on the effect when the rotor is turned clockwisefrom the central position. As another example, if the altered propertyof the input signal 316 may only vary at ten particular levels, then acertain arc of movement (for example, one full rotation) may be dividedinto ten ranges, with the range in which the rotor 106, 208 ispositioned being used as a trigger for activating one of the levels ofthe property.

For continuous properties, the program instructions 306 or circuitry mayassociate the property value with the rotational position in accordancewith some mathematical function. To determine such associations, therotary fader 100, 300 may receive an indication (or calculate from knownsystem limitations) of the maximum and minimum levels of the fade effectthat may be produced by the rotary fader. For example, if the fadedproperty were signal amplitude and the input signal 316 was representedby an analog electrical voltage, then the maximum value of the rotaryfader 100, 300 may be the highest voltage attainable (e.g., thesaturation level of the operational amplifiers in the rotary fader) andthe lowest value may be the lowest measurable voltage (e.g., the turn-onvoltage of the transistors). Then, the rotary fader 100, 300 maygenerate a range-scaling formula that associates the potential range ofvalues to the range of some rotational position arc (eitherpredetermined or dynamically allocated). Continuing the analog amplitudeexample, if the rotary fader 100, 300 designates two rotations of thefader control knob 102 (i.e., 720° or 4π radians) as the movement range,then the scaling formula may be determined by taking a template functionand assigning the scalars so that the minimum analog voltage isassociated with some zero position and the maximum level is associatedwith a position 720° beyond the zero position, in the directiondesignated for increasing amplitude (e.g., clockwise). Then, when therotary fader 100, 300 is producing the fade effect, the rotationalposition may be fed into the scaled function and the level of fading forthe property may be taken from the result of the function.

In some embodiments, a continuous property may be cast as a discreteproperty by assigning a smaller number of levels to the rotary fader100, 300. For example, an analog amplitude level may be converted to adigital signal during processing, such that only the discrete digitallevels are representable. However, in such an embodiment, the number ofdiscrete steps may be chosen so that the stepping is imperceptible to auser. In other embodiments, a continuous variable may be divided intoperceptibly large levels to be controlled by the rotary fader 100, 300.

In some embodiments, the fade effect may be produced continuously whilethe input signal 316 is being received. For example, one or more audiosignals may be continuously changed to allow a user to hear the effectof changes made to the signals, either independently or mixed together,or alternatively, to see the effects to a visual signal, while they arebeing tuned. In other cases, the fade or mix effect may be performedonly when detected user-interactions indicate an intent to alter thesignal. For example, the fade effect may only be activated while afade-on switch or button is actuated. As another example, the presenceof a user-hand on the fader control knob 102 may be detected (e.g., byheat, proximity, or pressure sensors on knob 102) and used as a triggerfor turning on or off the fade effect. In another aspect, the durationof a fade effect may be specified prior to the input signal 316 beingfully received, presented to the user, or cued up for fading. Forexample, when a user finds a certain “sweet spot” of fading for a trackor signal, the user may assign that fading level to the input signal 316for a time range after or before the portion of the signal that iscurrently being presented to the user (e.g., the rest of the track orthe whole track, including preceding and forthcoming portions). Inparticular, the rotary fader 100, 300 may record an indication of thepart of the input signal 316 that was presented when the fade-effectbegins to be altered (e.g., fader control knob 102 is moved) and, oncean acceptable level is attained, use that level (with a reasonablebuild-up) for a range of time that begins at the indicated part of thesignal.

At block 602 of the method 600, the method involves receiving anindication of a desired fade effect. In this and other contexts herein,the term “desired” is used as an indication of a prescribed, intended,or selected condition or level that is to be produced by the apparatus.However, the term should not be interpreted as requiring actual desireor want on the part of a user, artist, viewer, or other entity. Rather,the “desired” state of an apparatus is the state that the apparatus isbeing controlled to produce, whether or not that state is desired orexpected by a user or operator.

In the context of the block 602, the desired fade effect may be a stored(e.g., stored in the electronic storage 304, and/or a database incommunication with the rotary fader 100, 300) fade-effect level that therotary fader 100, 300 has been instructed to produce. In someembodiments, the stored level may be a fade level that was previouslytuned by a user of the rotary fader 100, 300 or a connected system. Forexample, the rotary fader 100, 300 may record a sequence of fade effectsthat a user tunes while the track is being recorded. The user may thenplay the track back including the sequence of fade effects. Therefore,the fade effect levels may be recorded as a level (or a position of thecontrol knob associated with that level) along with a correspondingtimestamp for the range over which the level is applied (or indicationsof which portion of the signal is contained in that range). Then, inreproducing the input signal 316 with the added effects, the rotaryfader 100, 300 may synchronize the recorded sequence of fade levels withthe received input signal to produce the playback. Such a process may beuseful so that the user may further fine-tune the fade effects uponhearing the playback.

As with other signals, the desired fade level (e.g., control input 320)may be received by a component of the rotary fader 100, 300 via any ofvarious interfaces, connections, and protocols. In some embodiments, thereceived control input features only the desired levels and timingsignals. In other embodiments, the rotary fader 100, 300 may receiverotor position specifications with the timing information, rather thanan indication of how the rotor position affects the signal. In stillother embodiments, the control input 320 may be received as levels ofstator current that are capable of moving the fader control knob 102 tothe desired position. Further, some control signals may be generated ina processing system, either in the fader or coupled to the rotary fader100, 300, which receives the input signal 316. For example, theprocessor 302 may be configured to recognize specific patterns in theinput signal 316 and, in response to recognizing the pattern,automatically tune the rotary fader 100, 300 to a particular level. Sucha recognizable pattern may be a volume range, a frequency range, achange in volume or frequency, a frequency profile, or a change infrequency profile; and may be detected by a signal processor in aprocessing system. In a mixing application, the rotary fader 100, 300may be programmed or configured to respond to patterns in one or bothtracks (including patterns in comparisons, correlations, or otheraggregate features) and alter the fade effect on each track inaccordance with the pattern recognition. In this way, dynamic changesdetected in one track may be used to change the fade levels in anothertrack.

At block 606, the method 600 includes rotating the fader control knob102 to a position associated with the desired effect. In an exampleembodiment, the motor 200 may be used to provide rotational forcethrough the rotor 106, 208 and the shaft 104 to control the fadercontrol knob 102. To do so, an electrical current of varying phase maybe applied to the stator coils 108 of the stator 206 of the motor 200.In particular, three-phase current may be input into stator coils 108 ofthe stator 206 in such a way that the induced magnetic fields eitheroppose or attract portions of the rotor 106, 208. When the rotor 106,208 achieves a magnetically-stable position, the current may be changedso as to rotate that stable position. In minimizing potential energy forthe rotary fader 100, 300, the rotor 106, 208 may then follow the stableposition in an electrically controllable pattern. Thereby, the rotaryfader 100, 300 may turn the fader control knob 102 to any position bychanging electrical current impulses through the stator coils 108. Toincrease the precision or stability of knob positioning, variousmonitoring/regulating mechanisms may be used on the control signal, suchas proportional-integral-derivative (PID) controllers or other feedbacksystems.

Further, the rotary fader 100, 300 uses the received desired fade effectin the block 602 as a controlling input for determining to whichposition to rotate the fader control knob 102 to. For example, if thedesired effect was recorded as a user-input to the rotary fader 100, 300(either in the same rotary fader or a different rotary fader setup),then the fader control knob 102 may be rotated to a position that isroughly the position of the fader control knob when the effect was firstrecorded. As another example, the rotary fader 100, 300 may determinepositions that may be associated with the desired fade-effect either byassigning discrete fade levels to particular position ranges of therotor 106, 208 and/or the fader control knob 102, or by generating afunction that associates a given amount of fade with a mathematicallycalculable position. As yet another example, the rotary fader 100, 300may be configured to react to the movement of another fader, so that oneor more faders may mirror, track or invert the movements of another.Once the controlling function (either discrete or continuous) has beengenerated, the sequence of desired fader levels may be converted to asequence of rotor positions, and used to move the rotor 106, 208 and thefader control knob 102 to the positions associated with the desiredeffect(s).

However, as stated above, one potential use of such an automatedplayback of fader levels is to facilitate changes to the fade levelbased on newly detected user-input. Accordingly, block 702 of the method700 includes detecting interference (e.g., by a user) with the movementof fader control knob 102. In context, the movement of the fader controlknob 102 is induced by the current in the stator 206 in the motor 200 inaccordance with a desired fade level. Accordingly, a user-interferenceof the movement may be an indication that the fade level should bechanged in the recorded sequence of fade effects. Hence, theuser-interaction may be treated as overriding, so that the fade effectthat is played by the rotary fader 100, 300 may be associated with theposition that the rotary fader is actually occupying, rather than therecorded fade level. In order to ensure that the user is able tointerfere effectively, the torque of the motor 200 may be relativelyweak in comparison to a user's strength. In some cases, this may beachieved by always applying a relatively low torque to the motor 200. Inother embodiments, the rotary fader 100, 300 may detect the presence ofa user-hand in proximity to the fader control knob 102 and, in response,temporarily lower the torque applied to the motor 200.

Further, since the user-interaction may indicate that the recorded faderlevel be changed, an example method 800 may include generatingindications of the actual position of the control knob (block 804) andstoring those indications along with timing information associated withthe actual positions (block 806). In some cases, the new fade-effectlevels or fader positions may be stored in databases in place of theoriginal fade levels (i.e., over-writing the original recorded sequenceof effects). In other cases, the new fade effects may be recorded in aseparate sequence of fade effects (along with the original fade effectswhenever the user did not interfere with the levels). In addition tostoring the position information for the rotor/knob, the system mayoptionally also record indications of the fade effect that was producedby the fader in accordance with the new position (block 808).

In another aspect of the present disclosure, the fader control knob 102that is tied directly to the motor 200 may facilitate producing a unique“feel” for the movement of the fade control knob. As discussed above,the gears, pulleys, connections, and motor friction may cause linearfaders to feel coggy or gritty. However, by connecting the fader controlknob 102 directly to the rotor 106, 208 of the motor 200, a majority ofthe physical feel of the rotary fader 100, 300 may be removed.Therefore, without any torque added by the motor 200, the fader controlknob 102 may glide easily with very little friction when rotating. Itshould be noted that the motor 200 may be a non-contact motor that maystill use some structures that make contact with the rotor/shaftassembly for mechanical support. However, such structures may be verylow friction (e.g., through bearings, lubricants, coatings, rollers,etc.) so as to be imperceptible to a user.

Nevertheless, it may be desirable to add some torque by the motor 200 inorder to improve the way that the fader control knob 102 feels whenturned, among other advantages. Accordingly, the torque of the motor 200(in either direction) may be utilized to oppose movement of fadercontrol knob 102 in order to produce a particular feel effect. Forexample, in one implementation, the motor 200 may be configured toprovide torque that resists all movement of the fader control knob 102by generating a certain (potentially quite small) opposing force on thefader control knob. In this way, a user may feel that the fader controlknob 102 is being resisted in a natural way. In addition to providing asingle continuous level of torque, the motor may 200 alternativelyprovide torque to cause the force applied to the fader control knob 102to vary with time, speed of rotation, or position so that force feelsmore natural and less manufactured than a continuous never changingforce. For example, a viscous feel may be provided when a small amountof force is applied in opposition to the direction of rotation, inproportion to the speed of rotation.

Specifically, a variable viscous component to the tactile feel of thefader control knob 102 may be desirable for preventing abrupt movementsand improving the ability of a user to more accurately fine-tune. Thenon-contact nature of the stator-support unit and the rotor-knob unit,as discussed above, may facilitate a viscous feel effect. In addition,dampers, whether mechanical, electrical (such as, via magneticcoupling), or a combination of electrical and mechanical, may be addedto achieve a viscous feel effect. In at least some embodiments, the term“viscous” or “viscosity” may be defined as a resistance/forceproportional to movement. An estimate for angular velocity may be usedto produce a viscous feel by adding a torque component in opposition tothe direction of rotation of the rotor 106, 208, in proportion to thespeed thereof. Particularly, the angular velocity for enhancing the feelof the control may be based on taking differences between Hall anglesensor samples with reference to the number of samples between them, andfiltering to mitigate the effects of noise and producing a digitalangular velocity signal.

In some embodiments, provided force on the fader control knob 102 by thetorque on the motor 200 may even include negative force (i.e., the motorpushing in the direction of rotation). However, the very low friction ofthe rotary fader 100, 300 may make such force unnecessary in mostapplications.

Turning now to FIGS. 9 and 10, methods 900 and 1000 show exampleprocedures that may be used in producing such an effect. As shown, themethods 900 and 1000 involve receiving a desired feel-effect setting atblocks 902 and 1002, respectively. The feel setting may be instructionsfor producing the desired feel-effect or it may simply provide a labelfor the feel-effect, for which procedures may be located through, forexample, reference to a hash table that includes feel labels andassociated procedures (block 1004). At blocks 904 and 1006, the methods900 and 1000 involve detecting user-interaction with the fader controlknob 102. Since the feel-effect may relate to the way the fader controlknob 102 feels in motion, the rotary fader 100, 300 may benefit fromdetecting the presence and characteristics of the user-interaction. Inparticular, some procedures may include different torque values fordifferent speed or acceleration values for the fader control knob 102.For example, if the desired feel-effect includes an indication of adesired level of perceived inertia for the fader control knob 102, thenmore torque may be applied to the motor 200 in response to a largeracceleration. Such torque values may be calculated in accordance withthe physical laws that govern the motion of objects with the particularinertia that is to be perceived.

Other feel effects may include the perception of friction, viscosity,virtual mass, dual-mode via push button, stabilization (e.g., with PIDor other feedback), a programmable texture, superposition, buzzing,end-stops notches, notch density, notch depth, moving notches, changingnotches (to appear or disappear), an audible “tick” produced by pulsingthe motor to simulate a (virtual) metallic mechanical stop, and asimulated spring load (substantially arbitrarily applied/simulated overany given range for the angular position of the fader control knob 102).As one example, a buzzing may be used to indicate that a limiting statehas been reached by the rotary fader 100, 300 or that some problem isoccurring. For instance, the buzzing may occur when the rotary fader100, 300 is turned too high. Buzzing or other tactile responses may alsoalert the user to changes or issues with the incoming signal (e.g.,signal level too high, signal is garbled, signal has ended, etc.)Similar tactile feedback may be provided to alert a user about any ofvarious state changes in the signal, the rotary fader 100, 300, oranother connected component (e.g., an audio mixer).

Some of the feel effects may fit into a category of “haptic” feedback,in which the force is perceived as a mechanical artifact of the rotaryfader 100, 300, though it is actually produced by electronic motorcontrols. For example, the rotary fader 100, 300 may simulate the feelof notches at different rotational positions by resisting movement awayfrom the set of stable positions associated with the notches, whileproviding less opposition to movement between notches. Because thenotches may be virtual, however, they may be moved and altered in bothlocation, number, and perceived depth (the amount of opposition tomovement away from the stable positions) depending on system state, asdiscussed above. As another example, a mechanical “tick” sound, coupledwith an end-stop (e.g., a positional threshold beyond which any furthermovement is greatly resisted by the motor), may provide the perceptionof the fader control knob 102 encountering a mechanical barrier at theend of the fader control knob's rotation path. As a further example, aspring-loading effect may be produced by providing a unidirectional (inone rotational direction but not the other) torque to the fader controlknob 102 that may increase as the fader control knob moves away from aparticular stable position. As still another example, a small buzz maybe provided when the rotary fader 100, 300 is moved in a translationalmanner, to communicate that movement has been recognized and make themovement feel more realistic.

In at least some embodiments, current in the motor 200 (e.g., currentthrough the stator coils 108 of the stator 206) may be set to zero whenthe desired feel effect involves no user interaction with the fadercontrol knob 102 and/or when the fader control knob is not being drivento a new position. Such a temporary disabling of the motor 200 mayextend the power/battery life of the motor. Furthermore, the rotaryfader 100, 300 may be designed such that the haptic features, discussedabove, may instantly or substantially instantly turn on (e.g., fasterthan a human may perceive) the motor 200 upon touching the fader controlknob 102. Such tactile sensing of the fader control knob 102 to turn themotor 200 on may be accomplished by using capacitive coupling and/or bysensing minute fluctuations in the Hall-sensor outputs, as discussedabove. Fluctuations determinable by the Hall-sensors may occur due tovibrations that may be caused by the presence of the user's fingers onthe fader control knob 102.

Therefore, such power-save features may be used to extend the batterylife of the motor 200 and/or reduce power consumption of the rotaryfader 100, 300. These power-save features may also be beneficial inreducing electromagnetic emissions (EMI emissions). Specifically, themotor driver chips responsible for providing pulse width modulated (PWM)signal(s) to each phase of the motor 200 may be disabled, therebysetting PWM outputs to the motor 200 to a high-impedance state, wheneverthe fader control knob 102 is not being touched by the user or beingdriven to a new position. In at least some embodiments, the motor drivermay be a Texas Instruments motor model number DRV8312, although othermotor drivers are contemplated and considered within the scope of thepresent disclosure.

Once disabled, the fader control knob 102 may essentially be consideredreleased, held only by a minute bearing/bushing friction. The speed ofde-activation or re-activation may be accomplished at a sufficient speedso as to render the de-activation/re-activation substantiallyimperceptible by the user, even when actively using the haptic features.Further, if the motor 200 drives are used to stabilize (hold steady) thefader control knob 102 in response to movement or vibration of therotary fader 100, 300 itself, the rotary fader may also be disabledif/when the rotary fader is not subject to any form of significantmotion/disturbance.

Depending on the implementation, there may be other chips that may alsobe turned off, such as power supplies, digital signal processors (DSPs)(in a multiple DSP system, where one DSP monitors all Hall sensors) oreven the bias current feeding the Hall sensors if an alternative meansof sensing touch (such as capacitive touch) is present.

Furthermore, three main methods may be considered to detecttouch/motion:

1) Small displacements detected via the Hall sensors—useful to detectthe presence of user interaction with the fader control knob 102 orrotation/error with respect to a desired position.

2) Capacitive touch sensing on the fader control knob 102.

3) Placing sensor(s) for the measurement of acceleration or velocity inthe rotary fader 100, 300 itself.

Other methods to detect touch/motion may include using infraredreflection or ultrasonic proximity detection for sensing the presence ofthe user's hand/fingers near or on the fader control knob 102. Suchinfrared reflection or ultrasonic proximity detection techniques mayalso advantageously provide some advance notice to the user as theuser's hand/fingers approach the fader control knob 102. In other cases,a small amount of back-EMF (or induced back-electromotive force) may beused to detect motion of the rotor 106, 208.

Other haptic, mechanical-mimicking, or other feel effects arecontemplated in the present disclosure, although not mentionedspecifically. Once the user-interactions are being tracked and the forcefor the feel effect has been calculated (block 1008), the rotary fader100, 300 may apply force to the rotor 106, 208, thereby providing asimulated feeling of resistance to the fader control knob 102 (block906). Since some user-interactions are quick and unexpected, the rotaryfader 100, 300 may maintain a certain opposition to motion, even whenthe fader control knob 102 is stopped and not moving. Additionally, thetorque may be provided as a circuit-based (rather than computer based)feedback loop, with the torque being the input, and the detected rotorposition being the output and feedback quantity. In any case, the forcemay be applied by sending electrical current through the stator coils108 (block 1010).

Additionally, in at least some embodiments, the rotary fader 100, 300may be used as an audio recording system (“audio recorder”). When usedas an audio recorder, the rotary fader 100, 300 may cease to operate asa fader, instead operating as an audio recorder that may utilize thecontactless construction of the motor 200 for operation. Specifically,in many audio applications, it may be desired to simulate end-stops onthe rotation of the fader control knob 102, allowing a user to perceivea mechanical limit to the angular rotation of the fader control knob. Inat least some embodiments, these mechanical limits may be placed aboutthree hundred degrees (300°) apart or about one hundred fifty degrees(150°) degrees from either side of top-center. Alternatively, in otherembodiments, it may be desirable to place deep notches or spring loadingalong sections of the angular travel of the fader control knob 102. Aspring may be electrically synthesized by applying a torque command thatmay be linearly ramped over any desired section of the angular travel.For example, these notches or spring loading sections may be used invarious modes to activate stop, play, record, next-file, previous-file,fast-forward (FF), and/or rewind (RR) functionality. Two configurationsof the fader control knob 102 being used as an audio recorder are shownin FIGS. 12 a and 12 b. In at least some embodiments, deep notches maybe desired at the next-file, previous-file and record settings, while alighter notch maybe desired at the play location, with spring loading asthe distance from play into either FF or RR being felt as a form offeedback as to how fast the FF or RR command commences.

Additionally, the angular position sensing from the Hall sensors,described above, may serve as the input to a state-machine for a devicebeing controlled by the fader control knob 102 used as an audiorecorder. Moreover, the inventors have found that the feel of anend-stop once the user forces the fader control knob 102 past theend-stop may be enhanced by adding a viscous component. This viscouscomponent differs from the previously described viscous feature inparagraphs [0076] and [0079]. Specifically, the viscous component whenusing the fader control knob 102 as an audio recorder may allow thedrive magnitude to diminish in a direction of travel back from theend-stop (toward the non-end-stop controlled region).

Advantageously, such a reduction of the angular momentum of the fadercontrol knob 102 may allow for an easier control of the fader controlknob and a reduced overshoot into the non-end-stop region upon thereturn of the fader control knob. Furthermore, in at least someembodiments, the feel of the end-stops of the fader control knob 102 maybe enhanced by deactivating all other features when within approximatelya few tenths to a few-hundredths of an electrical rotation prior toreaching the end-stop. Such a deactivation procedure may have an effectof making the electrical end-stop (with limitation on the availabletorque) appear/feel more dramatic.

Moreover, in at least some of those embodiments where the fader controlknob 102 controls actuation of the pushbutton 110, as described above,different positions of the pushbutton may be used for controlling themodes (stop, play, record, next-file, previous-file, fast-forward, andrewind) of the audio recorder. For example, in some embodiments, a firstposition (e.g., either in or out) of the pushbutton 110 may allow a userto implement a first subset of the audio recorder modes (e.g., play,record, next file, previous file), while a second position (again,either in or out) may allow the user to implement a second subset of theaudio recorder modes (e.g., fast-forward and rewind). The subset of theaudio recorder modes for each position of the pushbutton 110 are merelyexemplary. In other embodiments, the modes that may be associated witheach position of the pushbutton 110 may vary. Also, in at least some ofthose embodiments where the pushbutton 110 may be used to implement theaudio recorder, the speed of fast-forward/rewinding may be based on anamount of rotation of the fader control knob 102 either forward orbackward.

Additionally, the fader control knob 102 may be configured to beinterchangeable between the two configurations shown in FIGS. 12 a and12 b. Specifically, the fader control knob 102 may be configured suchthat a user may switch between the configurations of FIGS. 12 a and 12 bat any time. Notwithstanding the two configurations of the fader controlknob 102 that are shown in FIGS. 12 a and 12 b, other configurations ofthe fader control knob are contemplated and considered within the scopeof the present disclosure. Furthermore, the fader control knob 102 mayalso be used as a video recording system, instead of or in addition tobeing used as an audio recording system, as described above.

Thus, the combination of the various features described may provide amore favorable result than merely the sum of the parts. In particular,the geometry of the rotary fader 100, 300 may allow the fader controlknob 102 to be directly tied to the motor 200, without the use of gears,pulleys, etc. In combination with the motor 200, which is a non-contactmotor, the fader control knob 102 may provide very little opposition tomotion, which may be a greater reduction in opposition to motion thanwould be expected from the sum of the effect of these two featuresseparately. Additionally, the low opposition to motion, either from oneor both of the previous features, makes the haptic or “feel” effectsreasonably pursuable by reducing the external frictional forces to thepoint that the motor-produced effects feel realistic. Further still, theother features (e.g., rotary geometry, non-contact rotor, directconnection between the fader control knob 102 and the motor 200, “feel”effects) allow for the motorization/automation of the rotary fader 100,300 to be more efficient and natural-feeling than with rotary fadersthat may not include one or more of those features. It should not beconstrued that the features in this paragraph are the only novelfeatures of in the present disclosure, or that these features are moreimportant or preferable in an example embodiment. Rather, the examplefeatures are used to show that the features of the present disclosureproduce results that may not be expected by investigating each featureon its own. Therefore, the claimed systems and methods may not bereasonably interpreted as collections of separable elements, but ascohesive embodiments that provide inherent features not observable inthe separate elements alone.

Additionally, various modifications to the embodiments described aboveare contemplated and considered within the scope of the presentdisclosure. For example, in at least some embodiments, the rotor 106,208 may be flipped to face the top plate 112 and the fader control knob102 may be attached to a back portion of the rotor. Relatedly, in otherembodiments, the stator coils 108 may be placed outside (e.g.,surround), rather than inside the rotor 106, 208.

III. CONCLUSION

The construction and arrangement of the elements of the systems andmethods as shown in the exemplary embodiments are illustrative only.Although only a few embodiments of the present disclosure have beendescribed in detail, those skilled in the art who review this disclosurewill readily appreciate that many modifications are possible (e.g.,variations in sizes, dimensions, structures, shapes and proportions ofthe various elements, values of parameters, mounting arrangements, useof materials, colors, orientations, etc.) without materially departingfrom the novel teachings and advantages of the subject matter disclosed.

Additionally, in the subject description, the word “exemplary” is usedto mean serving as an example, instance or illustration. Any embodimentor design described herein as “exemplary” is not necessarily to beconstrued as preferred or advantageous over other embodiments ordesigns. Rather, use of the word exemplary is intended to presentconcepts in a concrete manner. Accordingly, all such modifications areintended to be included within the scope of the present disclosure. Anymeans-plus-function clause is intended to cover the structures describedherein as performing the recited function and not only structuralequivalents but also equivalent structures. Other substitutions,modifications, changes, and omissions may be made in the design,operating conditions, and arrangement of the preferred and otherexemplary embodiments without departing from scope of the presentdisclosure or from the scope of the appended claims.

Although the figures show a specific order of method steps, the order ofthe steps may differ from what is depicted. Also, two or more steps maybe performed concurrently or with partial concurrence. Such variationwill depend on the software and hardware systems chosen and on designerchoice. All such variations are within the scope of the disclosure.Likewise, software implementations could be accomplished with standardprogramming techniques with rule based logic and other logic toaccomplish the various connection steps, processing steps, comparisonsteps and decision steps.

What is claimed is:
 1. A fader apparatus comprising: a fader control knob directly attached to a rotor of a non-contact motor; a sensor system configured to detect a rotational position of the rotor; and control circuitry configured to cause a fade effect in accordance with the detected rotational position of the rotor.
 2. The fader apparatus of claim 1, further configured to: receive a signal representing a first desired fade effect; and in response to the received signal, provide torque sufficient to rotate the fader control knob to a position associated with the first desired fade effect.
 3. The fader apparatus of claim 2, wherein the sensor system is configured to detect a user-interaction moving the fader control knob to a second desired position different than the position associated with the first desired fade effect, and wherein the control circuitry is configured to cause the fade effect associated with the second desired position rather than the first desired fade effect, in response to the sensor system detecting the user-interaction.
 4. The fader apparatus of claim 3, wherein the sensor system is configured to transmit, to an electronic memory, indications of the second desired position of the fader control knob.
 5. The fader apparatus of claim 1, wherein the sensor system comprises one or more Hall-effect sensors configured to generate signals indicative of the rotational position of the rotor, in accordance with magnetic changes detected at the sensor system.
 6. The fader apparatus of claim 5, wherein the Hall-effect sensors are further configured to: generate signals indicative of a translational position of the rotor; and communicate the signals indicative of the translational position of the rotor to the control circuitry, wherein the control circuitry is configured to alter the fade effect in accordance with the indicated translational position of the rotor.
 7. The fader apparatus of claim 1, further comprising a pushbutton mounted within a movement range of the rotor, and wherein the pushbutton is configured to communicate a translational position of the rotor to the control circuitry.
 8. The fader apparatus of claim 1, wherein the non-contact motor is a brushless direct current electric motor.
 9. The fader apparatus of claim 1, wherein the rotor comprises a permanent-magnet rotor portion.
 10. The fader apparatus of claim 1, further configured to: receive a signal representing a desired feel effect for the fader control knob; receive, from the sensor system, an indication of a user-interaction with the fader control knob; and responsively control a stator current to provide a predetermined proportion of torque associated with the desired feel effect.
 11. The fader apparatus of claim 10, further comprising a database that associates a set of feel-effect options with procedures for creating a predetermined torque pattern for each of the set of feel-effect options.
 12. The fader apparatus of claim 1, wherein current through a stator of the non-contact motor creates a torque pattern as a function of the rotational position of the rotor to provide a set of stable rotation positions of the rotor.
 13. The fader apparatus of claim 12, wherein the set of stable rotational positions are programmable, and wherein a top plate situated under the fader control knob comprises markings that corresponds with second markings on the fader control knob to indicate positions for the fader control knob associated with the set of stable rotational positions of the rotor.
 14. The fader apparatus of claim 1, further configured to: receive control signals indicating a change in a notch configuration; and in response to receiving the control signals, adjust current to the stator to change at least one of a location of positions and a number of positions of a set of stable rotational positions of the rotor.
 15. The fader apparatus of claim 12, wherein the set of stable positions represent integer multiples of decibel levels for a fade effect of an audio signal.
 16. The fader apparatus of claim 1, wherein the apparatus is integrated into an audio mixer system.
 17. The fader apparatus of claim 1, wherein the apparatus is integrated into a video or audio recording system.
 18. A method for using a rotary fader apparatus, the method comprising: detecting, by a sensor system, a rotational position of a rotor of a non-contact motor, wherein the rotor is directly attached to a fader control knob; and in response to detecting the rotational position, control circuitry causing a fade effect in accordance with the detected rotational position of the rotor.
 19. The method of claim 18, further comprising: receiving a signal representing a desired fade effect; and in response to the received signal, providing torque sufficient to rotate the fader control knob to a position associated with the desired fade effect.
 20. The method of claim 19, further comprising: detecting a user-interaction that moves the fader control knob to a second position different than the position associated with the desired fade effect; and causing the fade effect associated with the second position rather than the desired fade effect, in response to detecting the user-interaction.
 21. The method of claim 18, further comprising: receiving a signal representing a desired feel effect for the fader control knob; receiving, from a sensor system, an indication of a user-interaction with the fader control knob; and responsively controlling a stator current to provide a predetermined proportion of torque associated with the desired feel effect.
 22. The method of claim 21, wherein the desired feel effect comprises a desired mass for the fader control knob, and wherein the predetermined proportion of torque is perceptually equivalent to a sensation experienced in turning another fader control knob with a physical mass equal to the desired mass.
 23. The method of claim 21, wherein responsively controlling the stator current comprises accessing a database that associates a set of feel-effect options with procedures for creating a predetermined torque pattern for each of the set of feel-effect options.
 24. A fader apparatus comprising: a fader control knob attached to a rotor of a non-contact motor, wherein the rotor is configured to: provide torque sufficient to rotate the fader control knob to a position associated with a desired fade effect, and wherein current through a stator of the non-contact motor is controlled to provide the torque of the non-contact motor associated with a desired feel effect when being operated by a user.
 25. The fader apparatus of claim 24, wherein providing the torque of the non-contact motor comprises providing an end-stop at a predetermined rotational limit.
 26. The fader apparatus of claim 24, wherein providing the torque of the non-contact motor comprises: receiving an indication of an alert state in a processing system coupled to the fader apparatus; and using the non-contact motor to provide a buzzing sensation to the fader control knob.
 27. The fader apparatus of claim 24, wherein providing the torque of the non-contact motor comprises using the non-contact motor to provide a notch-effect at each of a set of stable rotational positions.
 28. The fader apparatus of claim 23, wherein the fader apparatus is further configured to: receive control signals indicating a change in a notch configuration; and in response to receiving the control signals, adjust the current through the stator to change at least one of a location of positions and a number of positions of a set of stable rotational positions of the fader control knob.
 29. The fader apparatus of claim 28, further comprising changeable markings indicating knob orientations corresponding to the set of stable rotational positions, wherein the changeable markings are controlled by a system configured to change the markings in accordance with changes in the set of stable rotational positions.
 30. The fader apparatus of claim 24, wherein the desired feel effect comprises at least one of a friction effect, a viscosity effect, a perceived-mass effect, a stabilization effect, a programmable texture, a simulated spring load and an audible tick.
 31. The fader apparatus of claim 30, wherein the current through the stator of the non-contact motor is set to zero when the desired feel effect involves no user interaction with the fader control knob and the fader control knob is not being moved to a new position corresponding to a new fade effect
 32. The fader apparatus of claim 24, wherein the desired feel effect comprises a viscosity effect configured to prevent abrupt movements of the fader control knob. 